"Vinci absolutely denies the claims made by Sherpa. The group respects local labour laws and fundamental rights in Qatar as well as in all the countries where it operates," a Vinci spokesman said.

The Sherpa NGO said in a statement it had a submitted a claim in a French court against Vinci Construction Grand Projects and the managers of the Qatari unit QDVC for "forced labor" and "keeping someone in servitude".

Laetitia Liebert, Head of the Sherpa NGO, said that one of the NGO's lawyers traveled to Qatar and found that migrants worked 66 hours a week and had their passports confiscated.

"In Qatar, each QDVC collaborator has free access to his passport while work and rest times are strictly respected," the Vinci spokesman said in rebuttal, adding the company had notbeen notified of the claim.